In many cases, a torque converter is provided with a lock-up device for directly transmitting torque from a front cover to a turbine. The lock-up device includes: a piston that can be frictionally coupled to the front cover; a retaining plate fixed to the piston; a plurality of pairs of coil springs supported by the retaining plate; and a driven plate elastically coupled to the piston through the plurality of pairs of coil springs in the rotational direction. The driven plate is fixed to the turbine (see PTL 1).
Here, the piston axially divides the space between the front cover and the turbine. Torque of the front cover is configured to be transmitted to the lock-up device when a friction facing annularly attached to the outer peripheral part of the piston is pressed onto a friction surface of the front cover. Accordingly, the torque is transmitted from the lock-up device to the turbine. Fluctuation in torque to be inputted from an engine is herein absorbed and damped by the plurality of pairs of coil springs disposed in the outer peripheral part of the lock-up device.